Most of a large PDF's weight is images: scanned pages, photos, high-resolution graphics pasted in from elsewhere. Compressing a PDF means rewriting those images at a lower resolution and stronger compression, while leaving text and vector drawings alone.
Which level should I pick?
The file is rewritten with Ghostscript, using one of three standard profiles:
- Screen downsamples images to about 72 dpi. It gives the smallest files and is fine for reading on a phone or laptop, but photos look soft when zoomed or printed.
- Ebook, the default, downsamples to about 150 dpi. Good for email, sharing and office printing.
- Printer keeps images at about 300 dpi. The file shrinks less, but prints look as they should.
In every level, fonts are subset so only the characters actually used stay in the file, and text and vector graphics are kept as they are, so they stay crisp at any zoom. None of these is meant for a professional print shop; send them the original.
How much smaller will it get?
That depends on what is inside. A scanned document or a brochure full of photos often shrinks a lot. A PDF exported from a word processor with only text is already small and may barely change. If compressing would make the file bigger, you get your original back unchanged, so you never end up with a worse file.
Where are my files processed?
Compression runs on our server, not in your browser. The PDF is uploaded over an encrypted connection, processed in Germany, and deleted automatically within two hours. If a file is too sensitive to upload at all, keep it on your device and use a desktop tool instead.
What are the limits?
Single PDFs up to 50 MB are free without an account, within a daily allowance of 20 server jobs (50 with a free account). Pro removes the allowance and accepts files up to 500 MB. Compression is a common first step in a recipe: the Scan cleanup preset in the pipeline builder compresses each PDF and then pulls out its text with OCR. You can try a pipeline on up to 3 files for free.
How to compress a PDF
- Drop your PDF onto the drop zone.
- Choose screen, ebook or printer, or keep ebook.
- Click Compress and wait a few seconds.
- Compare the new size with the old one and download the result.
FAQ
Will compression make the text blurry?
No. Text is kept as text and stays sharp. Only images are downsampled.
Can I compress a password-protected PDF?
Remove the password with Unlock PDF first, then compress, then add the password back with Protect PDF if you need it.
Why did my PDF barely shrink?
It probably contains few images. Text-only PDFs are already compact, and there is little to remove. Try the screen level if you need every kilobyte.
Does compression remove form fields or links?
Links are kept. Interactive form fields and digital signatures may not survive the rewrite, so fill and sign forms after compressing.
How long does it take?
Usually a few seconds. Long scanned documents with many large images take longer.